instance

问题 I understand the concept of Static and Instance but I am confused which I should use when I have a class of which only 1 instance will ever exist which is the instance which is called at the start of my application (=Application.Current.MainWindow) I want to keep a list which I need thoughout different classes the whole time in my program. Should I make it static because there won't ever exist 2 instances of MainWindow? Or should I make it non-static since it sounds right saying that it

问题 I understand the concept of Static and Instance but I am confused which I should use when I have a class of which only 1 instance will ever exist which is the instance which is called at the start of my application (=Application.Current.MainWindow) I want to keep a list which I need thoughout different classes the whole time in my program. Should I make it static because there won't ever exist 2 instances of MainWindow? Or should I make it non-static since it sounds right saying that it

问题 I would like to know if there is any way I can destroy a Codeigniter library instance. What I want to do is something like this: $this->load->library('my_library'); /** Code goes here **/ $this->my_library->destoy_instance(); The reason I need to do this is because I need to liberate RAM memory while executing a large scripts. Any help will be greatly appresiated. 回答1: You can do simply like that by using unset or setting null . unset($this->my_library); OR $this->my_library = null; This

问题 In Java, I have 2 classes. One contains a JFrame. On startup, that class is called. The JFrame shows. But in the other class, when I press a button on it's own frame, it opens a new instance of that class which should make another frame. But it just focuses on the old frame already opened... Source: FrameToOpen.java public FrameToOpen() { JFrame frame = new JFrame(); // Just the most simple settings to make it appear... frame.setSize(400, 200); frame.setVisible(true); } OtherClass.java public

问题 In Java, I have 2 classes. One contains a JFrame. On startup, that class is called. The JFrame shows. But in the other class, when I press a button on it's own frame, it opens a new instance of that class which should make another frame. But it just focuses on the old frame already opened... Source: FrameToOpen.java public FrameToOpen() { JFrame frame = new JFrame(); // Just the most simple settings to make it appear... frame.setSize(400, 200); frame.setVisible(true); } OtherClass.java public

问题 What is a better approach for implementing converter from DTO to Entity? Using factory with static methods to convert or using instance Converter object? 回答1: Finally I ended with instance Converter objects as they may be mocked, that is better for testing 来源： https://stackoverflow.com/questions/13176707/static-methods-to-transform-dto-to-entity

问题 There is something that i don't understand about ruby class instance variable or methods** . So i have this code that keeps on giving me this error and i cant understand Looks ruby thinks that i am trying to call for Float.in_celsius but I want to make this call within my class instance. #----------------------------------- def ftoc(fr) fr = fr.to_f if (fr == 32) c = 0 elsif (fr == 212) c = 100 else c = (fr-32.0)*(5.0/9.0) end return c end def ctof (cl) cl = cl.to_f f = (cl*(9.0/5.0))+32.0

问题 I have rewritten a VB6 application in Delphi. It should have only one instance running. How can I do this with minimum of code? In VB6 we just have to use one single line of code > If App.PrevInstance Then 'Take some action End If On goggling I did find a solution but it is very length and we have to mess with .drp file. I do not want to do that. I want something simpler. 回答1: I have some code along the lines of: var AppMutex: THandle; { .... } initialization // Create the mutex AppMutex :=

问题 Maybe the title is a little screwed up but is there a way to make an instance of a class inside the same class in Python? Something like this: class Foo: foo = Foo() I know that the interpreter says that Foo is not declared but is there a way to achieve this? Update: This is what I'm trying to do: class NPByteRange (Structure): _fields_ = [ ('offset', int32), ('lenght', uint32), ('next', POINTER(NPByteRange)) ] 回答1: The interpreter only minds if you try to do it in a context where Foo is not

问题 I'm having a problem. I want to get the current function scrope. I have this example code that i'm working ok. function nittle(){ var Pen = new Dot(); // Generated dynamical through eval() ..... for(key in window) { if( window[key] instanceof Dot ){ alert("found it"); } } } But it seems not to work within the function scope. Work outside of it. Is there a work around ? Thanks. 回答1: I'm not aware of any way to determine programmatically what variables have been declared inside a function,